Zimbra Desktop 7.1.2 disappearing spam

Since upgrading from 7.0.x to 7.1.2, when I mark mail as "read" in my junk folder (on a ZCS account), the mail disappears (this generally happens within a few seconds). It's still present in the folder if I use the ZCS web interface, but it seems to be removed from my local folder... this means I can't use ZD to mark something as not spam if I want to etc... any ideas?